A hit by even one of the smaller [asteroid] rocks, say the size of a convenience store, would have the impact of 400,000 Hiroshima nuclear bombs exploding at once, he says. The larger varieties (a mile or more in diameter) could hit with as much force as millions of Hiroshima bombs, with devastating planet-wide effects, such as tsunamis, damage to the atmosphere, and radical climate change, with the magnitude of the damage depending on how big it the object is, its composition and if it hits land or water.Several space programs do currently track NEOs to identify asteroids on a possible collision course with Earth, but these programs are not well coordinated and do not have the funding to track a sufficient number of objects. The ASE plans to deliver a proposal to the UN for a coordinated network of telescopes to better identify and track these asteroids. Although it is not the ASE's role to develop action plans in the event an asteroid threat is detected, its members have contemplated ways to avoid a collision:
In addition to telescopes to detect an incoming rock, that technology could include flying a spacecraft alongside an asteroid that is on course to impact our world. [NEO committee chairman Rusty] Schweickart says the gravitational attraction between the vessel and the space rock would tug on the latter just enough to alter its course and miss Earth. Another, less appealing option would be to shatter or blow up an approaching asteroid.But is the risk of such an impact real, or is it just movie-engendered hype?
"It's real," says John Pike, director of Globalsecurity.org, an informational Web site focused on security issues, including space. "It's not a question of whether it's going to happen, it's just a question of when it's going to happen."What 'Deep Impact' might an asteroid make on Earth, astronauts ask and Will an asteroid destroy Earth? Time for UN to keep tabs, say experts [Scientific American]